The present invention relates to a shift control system and a control apparatus and method for a belt-type continuously variable transmission.
Japanese Laid-Open Patent Publication No. 7-217712 discloses a belt-type continuously variable transmission (CVT) of which transmission ratio is controlled in response to a vehicle speed and a throttle valve opening. The CVT has selectable shift ranges including a normal driving range (generically known as D range) and a so-called engine braking range (such as such as L range or 1 range, 2 range or Ds range). When the normal driving range is selected, the transmission ratio is controlled according to a shift pattern within a normal driving ratio control region. When the engine braking range is selected, the transmission ratio is controlled according to a shift pattern within an engine braking ratio control region that has a minimum ratio value greater than that of the normal driving ratio control region.